In this tutorial, we will show you how to enable BBR on Ubuntu 20.04 LTS. For those of you who didn’t know, Bottleneck Bandwidth and Round-trip propagation time, or BBR, is a congestion control algorithm that powers traffic from google.com and YouTube, Google Cloud Platform, and Internet Engineering Task Force (IETF). Google developed the algorithm, and it can produce higher throughput and lower latency for traffic from your server.
This article assumes you have at least basic knowledge of Linux, know how to use the shell, and most importantly, you host your site on your own VPS. The installation is quite simple and assumes you are running in the root account, if not you may need to add ‘sudo‘ to the commands to get root privileges. I will show you the step-by-step configure BBR on Ubuntu 20.04 (Focal Fossa). You can follow the same instructions for Ubuntu 18.04, 16.04, and any other Debian-based distribution like Linux Mint.
Prerequisites
- A server running one of the following operating systems: Ubuntu 20.04, 18.04, 16.04, and any other Debian-based distribution like Linux Mint.
- It’s recommended that you use a fresh OS install to prevent any potential issues.
- SSH access to the server (or just open Terminal if you’re on a desktop).
- An active internet connection. You’ll need an internet connection to download the necessary packages and dependencies.
- A
non-root sudo useror access to theroot user. We recommend acting as anon-root sudo user, however, as you can harm your system if you’re not careful when acting as the root.
Enable BBR on Ubuntu 20.04 LTS Focal Fossa
Step 1. First, make sure that all your system packages are up-to-date by running the following apt commands in the terminal.
sudo apt update sudo apt upgrade
Step 2. Check and Upgrade Your Kernel.
BBR requires Linux kernel version 4.9 or above. Since Ubuntu 20.04 comes with the 5.4.0 kernel, we can enable BBR right away. To check your current kernel version, run this command below:
uname -r
Step 3. Enable BBR on Ubuntu 20.04.
The instructions below are the same for both Debian and Ubuntu. First, run the following command to check available congestion control algorithms:
sysctl net.ipv4.tcp_available_congestion_control
Output:
net.ipv4.tcp_available_congestion_control = reno cubic
Next, check the current congestion control algorithm used in your Ubuntu system:
sysctl net.ipv4.tcp_congestion_control
Output:
net.ipv4.tcp_congestion_control = cubic
After that, open the following configuration file /etc/sysctl.conf to enable TCP BBR:
nano /etc/sysctl.conf
Add the following file:
net.core.default_qdisc=fq net.ipv4.tcp_congestion_control=bbr
Save and exit sysctl.conf, then refresh with your new configuration:
sysctl -p
You can check the congestion control algorithm in use with:
sysctl net.ipv4.tcp_congestion_control
Output:
net.ipv4.tcp_congestion_control = bbr
Congratulations! You have successfully set up BBR. Thanks for using this tutorial to enable BBR on Ubuntu 20.04 LTS Focal Fossa system. For additional help or useful information, we recommend you check the official Ubuntu website.
